Contribution Margin Calculator
Contribution margin is what each sale contributes toward fixed costs and profit. Calculate it per unit, as a ratio, and in total, and see how many units you need to cover your overhead.
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Book Your Free 30-Min Call →Contribution Margin vs Gross Margin
They are often confused and they are not the same thing. Gross margin deducts cost of goods sold, which usually mixes variable costs with some fixed ones — factory rent and supervisor salaries sit in COGS but don't move with volume. Contribution margin deducts only genuinely variable costs: materials, direct labour paid per unit, shipping, payment processing, sales commission.
That distinction is what makes contribution margin the right tool for decisions. When you are asking "should I take this order at a discount?" or "which product line should I push?", the only costs that matter are the ones that change with the answer. Fixed costs are getting paid either way.
The Discount Decision
Contribution margin is what tells you whether a discounted order is worth taking. If a unit sells for $120 with $72 of variable cost, the contribution is $48. A customer offering $90 still contributes $18 per unit toward fixed costs — worth taking if you have spare capacity and it doesn't cannibalise full-price sales. A customer offering $70 contributes nothing and costs you $2 a unit to serve.
The trap is doing this repeatedly. Marginal pricing is sound for genuinely marginal volume; it becomes ruinous when it turns into your standard price. Once discounted work fills the capacity that full-price work would have used, the contribution you gave up is real.
By Product, Not in Aggregate
A blended, whole-business contribution margin hides everything worth knowing. Most businesses have a small number of products or services carrying the whole operation, and a long tail contributing little or actively losing money once you look properly. Running this calculation line by line is usually the single most revealing hour a small business owner can spend on their numbers — and it very often overturns assumptions about which work is worth chasing.
Pair it with our break-even calculator for the fixed-cost side, and our profit margin calculator for the reported margin view.
Frequently Asked Questions
What is a good contribution margin ratio?
It varies by model. Software and digital products can exceed 80% because variable cost per additional customer is near zero. Manufacturing often sits at 25-40%, and distribution can be under 20%. What matters is whether total contribution comfortably exceeds your fixed costs.
Is sales commission a variable cost?
Yes, if it is paid per sale. Anything that only occurs because a unit was sold belongs in variable cost — commission, payment processing fees, shipping, packaging. A sales salary paid regardless of volume is a fixed cost.
Can contribution margin be negative?
Yes, and it means you lose money on every unit sold. Volume makes it worse, not better. Either the price is too low or the variable cost is higher than you believed, and no amount of growth will fix it.
How does this relate to break-even?
Break-even units equal fixed costs divided by contribution margin per unit. Contribution margin is the engine of the break-even calculation — each unit's contribution chips away at fixed costs until they are covered.